Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 8 Jan 2021 08:56:20 -0800
From:   Sean Christopherson <seanjc@google.com>
To:     Steve Rutherford <srutherford@google.com>
Cc:     Ashish Kalra <ashish.kalra@amd.com>,
        "Dr. David Alan Gilbert" <dgilbert@redhat.com>,
        "Singh, Brijesh" <brijesh.singh@amd.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Joerg Roedel <joro@8bytes.org>,
        Borislav Petkov <bp@suse.de>,
        "Lendacky, Thomas" <Thomas.Lendacky@amd.com>,
        X86 ML <x86@kernel.org>, KVM list <kvm@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "dovmurik@linux.vnet.ibm.com" <dovmurik@linux.vnet.ibm.com>,
        "tobin@ibm.com" <tobin@ibm.com>,
        "jejb@linux.ibm.com" <jejb@linux.ibm.com>,
        "frankeh@us.ibm.com" <frankeh@us.ibm.com>,
        "Grimm, Jon" <jon.grimm@amd.com>
Subject: Re: [PATCH v2 1/9] KVM: x86: Add AMD SEV specific Hypercall3
Message-ID: <X/iOtPo7/EoB6ban@google.com>
References: <20201218193956.GJ2956@work-vm>
 <E79E09A2-F314-4B59-B7AE-07B1D422DF2B@amd.com>
 <20201218195641.GL2956@work-vm>
 <20210106230555.GA13999@ashkalra_ubuntu_server>
 <CABayD+dQwaeCnr5_+DUpvbQ42O6cZBMO79pEEzi5WXPO=NH3iA@mail.gmail.com>
 <20210107170728.GA16965@ashkalra_ubuntu_server>
 <X/dEQRZpSb+oQloX@google.com>
 <20210107184125.GA17388@ashkalra_ubuntu_server>
 <X/dfjElmMpiEvr9B@google.com>
 <CABayD+fHUSVCQP7muax5E-ZbAVMt0g1vXYjtJ22+m_+Y5SE=2Q@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CABayD+fHUSVCQP7muax5E-ZbAVMt0g1vXYjtJ22+m_+Y5SE=2Q@mail.gmail.com>
Precedence: bulk

On Thu, Jan 07, 2021, Steve Rutherford wrote:
> Supporting merging of consecutive entries (or not) is less important
> to get right since it doesn't change any of the APIs. If someone runs
> into performance issues, they can loop back and fix this then. I'm
> slightly concerned with the behavior for overlapping regions. 

I'm assuming merging entries will be a near-trivial effort once everything else
is implemented, e.g. KVM will need to traverse the list to remove entries when
address are converted back to private.  Piling on merging functionality at that
point should not be all that hard, especially if the list is sorted and entries
are merged on insertion.